1/*
2 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/entity/BasicHttpEntity.java $
3 * $Revision: 496070 $
4 * $Date: 2007-01-14 04:18:34 -0800 (Sun, 14 Jan 2007) $
5 *
6 * ====================================================================
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements.  See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership.  The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with the License.  You may obtain a copy of the License at
14 *
15 *   http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied.  See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 * ====================================================================
24 *
25 * This software consists of voluntary contributions made by many
26 * individuals on behalf of the Apache Software Foundation.  For more
27 * information on the Apache Software Foundation, please see
28 * <http://www.apache.org/>.
29 *
30 */
31
32package org.apache.http.entity;
33
34import java.io.IOException;
35import java.io.InputStream;
36import java.io.OutputStream;
37
38/**
39 * A generic streamed entity being received on a connection.
40 *
41 * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
42 *
43 * @version $Revision: 496070 $
44 *
45 * @since 4.0
46 */
47public class BasicHttpEntity extends AbstractHttpEntity {
48
49    private InputStream content;
50    private boolean contentObtained;
51    private long length;
52
53    /**
54     * Creates a new basic entity.
55     * The content is initially missing, the content length
56     * is set to a negative number.
57     */
58    public BasicHttpEntity() {
59        super();
60        this.length = -1;
61    }
62
63    // non-javadoc, see interface HttpEntity
64    public long getContentLength() {
65        return this.length;
66    }
67
68    /**
69     * Obtains the content, once only.
70     *
71     * @return  the content, if this is the first call to this method
72     *          since {@link #setContent setContent} has been called
73     *
74     * @throws IllegalStateException
75     *          if the content has been obtained before, or
76     *          has not yet been provided
77     */
78    public InputStream getContent()
79        throws IllegalStateException {
80        if (this.content == null) {
81            throw new IllegalStateException("Content has not been provided");
82        }
83        if (this.contentObtained) {
84            throw new IllegalStateException("Content has been consumed");
85        }
86        this.contentObtained = true;
87        return this.content;
88
89    } // getContent
90
91    /**
92     * Tells that this entity is not repeatable.
93     *
94     * @return <code>false</code>
95     */
96    public boolean isRepeatable() {
97        return false;
98    }
99
100    /**
101     * Specifies the length of the content.
102     *
103     * @param len       the number of bytes in the content, or
104     *                  a negative number to indicate an unknown length
105     */
106    public void setContentLength(long len) {
107        this.length = len;
108    }
109
110    /**
111     * Specifies the content.
112     *
113     * @param instream          the stream to return with the next call to
114     *                          {@link #getContent getContent}
115     */
116    public void setContent(final InputStream instream) {
117        this.content = instream;
118        this.contentObtained = false;
119    }
120
121    // non-javadoc, see interface HttpEntity
122    public void writeTo(final OutputStream outstream) throws IOException {
123        if (outstream == null) {
124            throw new IllegalArgumentException("Output stream may not be null");
125        }
126        InputStream instream = getContent();
127        int l;
128        byte[] tmp = new byte[2048];
129        while ((l = instream.read(tmp)) != -1) {
130            outstream.write(tmp, 0, l);
131        }
132    }
133
134    // non-javadoc, see interface HttpEntity
135    public boolean isStreaming() {
136        return !this.contentObtained && this.content != null;
137    }
138
139    // non-javadoc, see interface HttpEntity
140    public void consumeContent() throws IOException {
141        if (content != null) {
142            content.close(); // reads to the end of the entity
143        }
144    }
145
146} // class BasicHttpEntity
147